Study the effect of using selenium resources and amounts on stress susceptibility indexes to wheat cultivars in Maragheh rainfed region conditions

Randomised complete block design with the three-factor factorial test was executed with three replications in the garden ۱۰ km away from Maragheh-Hashtrud road in the ۲۰۱۷-۲۰۱۸ agricultural year to study the effect of various resources and amounts of selenium, yield components, and stress susceptibility indexes to wheat cultivars. The experimental treatments include factor (a) of various selenium resources (sodium selenate and selenite index), factor (b) of various selenium amounts (۰, ۱۸, and ۳۶ g/ha), and factor (c) of three wheat cultivars (Azar ۲, Pishtaz, and Sardari). The characteristics of yield, yield components, stress susceptibility index (SSI), tolerance index (TOL), mean productivity (MP), geometrical mean productivity (GMP), yield index (YI), and yield stability index (YSI) were examined. The yield of wheat cultivars in drought stress conditions (not using selenium) (Ys) and in normal conditions (using selenium) (Yp) was used to estimate the tolerance index and drought susceptibility index. The mean factor a level from various selenium resources (sodium selenate and selenite) showed that using selenite is prior than selenate in all three characteristics of grain weight, yield in spike, and weight of thousand grains. The selenite treatment was selected as the prior treatment, and then it was examined based on the mentioned characteristics and estimation of SSI and TOI. The results from variance analysis showed a significant difference between the yield and yield components of cultivars in the normal conditions (۱۸ and ۳۶ g/ha of sodium selenite) and water stress (non-usage of selenium). The grain means yield and weight in the spike of the studied genotypes in the normal condition (۱۸ and ۳۶ g/ha selenite) were ۱۷۵۲.۸۳ kg/ha ۰.۵۹۱ g and ۱۷۹۰.۸۲ kg/ha and ۰.۵۹ g, respectively. Pishtaz and Sardari genotypes in normal conditions (۱۸ and ۳۶ g/ha sodium selenite) and water stress (non-usage of selenium) had the maximum and minimum yield. The grain yield of Pishtaz is significantly higher than Azar ۲ and Sardari cultivars in the normal conditions (۱۸ and ۳۶ g/ha sodium selenite), while it was indicated by imposing the water stress (non-usage of selenium) that water stress has a weaker effect on grain yield of Azar ۲ and Sardari cultivars but it significantly reduced the grain yield of Pishtaz cultivar as grain yield of Pishtaz cultivar was more than Azar ۲ and Sardari cultivars in water stress condition (non-usage of selenium). In this research, the Pishtaz cultivar had the maximum stress tolerance in both conditions of ۱۸ and ۳۶ g/ha sodium selenite with a mean of ۱.۰۵ and ۱.۰۲, respectively whereas the Sardari cultivar showed the minimum stress tolerance with a mean of ۰.۹۴ and ۰.۹۲, respectively.

Keywords:

wheat , sodium selenate , sodium selenite , yield and yield components , SSI